High Quality Delivery Valve 1W6987 Diesel Engine Spare Parts

As a precision part in the fuel injection system, the maintenance quality of the oil delivery valve directly affects the injection accuracy, power performance and service life of the engine. The following are the core maintenance points of the oil delivery valve, which need to be carried out in combination with regular inspection, cleaning, calibration and fault prevention:

Regular inspection: Identify early fault signals
Appearance inspection
After disassembling the injection pump, take out the oil delivery valve parts (valve head and valve seat), rinse the surface with clean diesel, and observe:
Sealing cone surface: whether there are scratches, pits, depressions or rust (if present, it will cause seal failure);
Decompression ring belt: whether the surface is smooth and whether there are steps formed by wear (you can scratch it lightly with your fingernail, and it is normal if there is no obvious jamming);
Guide part: whether the match with the inner hole of the valve seat is smooth, without stagnation or looseness (when shaking the valve stem, there should be no obvious radial clearance).
Sealing test
Simple test: Invert the oil outlet valve pair, inject clean diesel into the valve seat, block the oil outlet with your finger and press the valve head. If there is no diesel leakage and the valve head can slowly reset, it means that the seal is good;
Professional test: On the injection pump test bench, apply rated pressure (such as 150-200bar) to the oil outlet valve, observe the pressure drop value within 1 minute, and if it exceeds 5bar, it is considered to be a poor seal.
Fitting clearance inspection
The standard fitting clearance between the oil outlet valve and the valve seat is 0.001-0.003mm, and the maximum allowable value does not exceed 0.005mm;
It can be measured with a feeler gauge or a special measuring tool. If the clearance is too large, it will cause fuel leakage and pressure drop, and the whole set of pairs needs to be replaced (the valve head or valve seat cannot be replaced alone, otherwise it will affect the fitting accuracy).

Cleaning and maintenance: avoid impurities and wear
Cleaning principles
During the disassembly and assembly process, it is necessary to operate in a clean environment to avoid dust and fiber impurities entering the mating surface of the parts;
When cleaning, filtered clean diesel (or special cleaning agent) must be used, and kerosene and gasoline are prohibited (may corrode metal or leave impurities);
You can use a soft brush to lightly brush the surface, and it is strictly forbidden to use hard tools such as steel balls and sandpaper to grind (it will scratch the precision surface).
Fuel system pre-protection
The wear of the oil outlet valve is mostly caused by impurities in the fuel, and fuel filtration needs to be strengthened:
Regularly replace the fuel filter (according to the manual requirements, usually every 20,000-30,000 kilometers), and use the original or qualified filter element (filtration accuracy ≤5μm);
Avoid mixing water or impurities when refueling (if you choose a regular gas station, keep the fuel tank cap well sealed), and regularly drain the accumulated water at the bottom of the fuel tank (especially in humid areas).

Maintenance of key components: spring and installation details
Inspection of oil outlet valve spring
Check whether the spring is deformed, broken, rusted, or whether the two ends are worn (which will cause uneven force);
Test elastic force: compress the spring by hand to feel whether the elastic force is uniform. If there is obvious weakness or jamming, it needs to be replaced in time (spring failure will cause the oil outlet valve to close lagging and affect the injection timing).
Installation precautions
During assembly, it is necessary to ensure that the oil outlet valve parts are clean and free of oil stains (avoid adsorption of impurities after installation), and tighten the fixing nut according to the original torque (too loose will cause leakage, too tight may crush the valve seat);
After installation, push the valve stem manually to ensure flexible movement without jamming. If there is a sense of blockage, it is necessary to recheck whether there are impurities or assembly misalignment.

Targeted treatment after failure
Poor sealing (leakage)
If the seal fails due to slight scratches, you can try grinding in pairs (use special grinding paste, grind lightly in a clockwise direction to avoid excessive grinding resulting in increased fit clearance);
In case of severe wear or deformation, the whole set of parts must be replaced (different batches of valve heads and valve seats cannot be mixed).
Failure of the pressure relief ring
If the residual pressure is too high due to the wear of the pressure relief ring (manifested as dripping and black smoke from the injector), the pairing parts need to be replaced directly and cannot be repaired (the worn ring cannot restore its original accuracy).
Insufficient spring force
When replacing a new spring, it is necessary to select a model that is consistent with the original factory parameters (elastic force, free length, and wire diameter must all match) to avoid abnormal valve head closing pressure due to parameter mismatch.

Precautions in daily use
Avoid inferior fuel: Long-term use of low-grade or impurity-exceeding fuel will accelerate the wear and carbon deposition of the oil outlet valve. It is recommended to select fuel that meets the engine requirements (such as diesel vehicles using National VI standard diesel);
Regular maintenance of the injection pump: Perform a comprehensive overhaul of the injection pump according to the manual requirements (usually every 100,000-150,000 kilometers), and simultaneously check the status of the oil outlet valve to avoid indirect effects on the oil outlet valve due to failures of other components (such as plunger wear);
Cold start protection: In a low temperature environment, the engine needs to be preheated to normal temperature before loading the load to avoid abnormal wear of the oil outlet valve due to high fuel viscosity and large pressure fluctuations.

Through the above maintenance measures, the service life of the oil delivery valve can be effectively extended, and the accuracy of the fuel injection system can be ensured, thereby ensuring that the engine has strong power, reasonable fuel consumption and meets emission standards.